fix: crash when changing rgs server

CHANGELOG.md

@@ -8,6 +8,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 ## [Unreleased]
 
 ### Fixed
+- Fix ANR on RGS server settings screen caused by catastrophic regex backtracking #880
 - Fix crash when returning app to foreground on Receive screen #875
 - Show loading state on Spending tab when node is not running #875
 

app/src/main/java/to/bitkit/di/HttpModule.kt

@@ -12,10 +12,14 @@ import io.ktor.client.plugins.defaultRequest
 import io.ktor.client.plugins.logging.LogLevel
 import io.ktor.client.plugins.logging.Logging
 import io.ktor.client.plugins.logging.LoggingConfig
+import io.ktor.client.request.head
 import io.ktor.http.ContentType
 import io.ktor.http.contentType
+import io.ktor.http.isSuccess
 import io.ktor.serialization.kotlinx.json.json
 import kotlinx.serialization.json.Json
+import to.bitkit.utils.UrlValidator
+import to.bitkit.utils.AppError
 import to.bitkit.utils.Logger
 import javax.inject.Singleton
 import io.ktor.client.plugins.logging.Logger as KtorLogger
@@ -43,6 +47,17 @@ object HttpModule {
         }
     }
 
+    @Provides
+    @Singleton
+    fun provideUrlValidator(httpClient: HttpClient) = UrlValidator { url ->
+        runCatching {
+            val response = httpClient.head(url)
+            if (!response.status.isSuccess()) {
+                throw AppError("Server returned '${response.status}'")
+            }
+        }
+    }
+
     @Suppress("MagicNumber")
     private fun HttpTimeoutConfig.defaultTimeoutConfig() {
         requestTimeoutMillis = 60_000

app/src/main/java/to/bitkit/repositories/LightningRepo.kt

@@ -79,6 +79,7 @@ import to.bitkit.services.NodeEventHandler
 import to.bitkit.utils.AppError
 import to.bitkit.utils.Logger
 import to.bitkit.utils.ServiceError
+import to.bitkit.utils.UrlValidator
 import java.io.File
 import java.util.concurrent.ConcurrentHashMap
 import java.util.concurrent.atomic.AtomicBoolean
@@ -105,6 +106,7 @@ class LightningRepo @Inject constructor(
     private val preActivityMetadataRepo: PreActivityMetadataRepo,
     private val connectivityRepo: ConnectivityRepo,
     private val vssBackupClientLdk: VssBackupClientLdk,
+    private val urlValidator: UrlValidator,
 ) {
     private val _lightningState = MutableStateFlow(LightningState())
     val lightningState = _lightningState.asStateFlow()
@@ -619,6 +621,11 @@ class LightningRepo @Inject constructor(
     suspend fun restartWithRgsServer(newRgsUrl: String): Result<Unit> = withContext(bgDispatcher) {
         Logger.info("Changing ldk-node RGS server to: '$newRgsUrl'", context = TAG)
 
+        validateRgsUrl(newRgsUrl).onFailure {
+            Logger.warn("RGS server unreachable at '$newRgsUrl'", it, context = TAG)
+            return@withContext Result.failure(it)
+        }
+
         waitForNodeToStop().onFailure { return@withContext Result.failure(it) }
         stop().onFailure {
             Logger.error("Failed to stop node during RGS server change", it, context = TAG)
@@ -640,6 +647,12 @@ class LightningRepo @Inject constructor(
         }
     }
 
+    private suspend fun validateRgsUrl(url: String): Result<Unit> = withContext(bgDispatcher) {
+        val initialTimestamp = 0
+        val testUrl = "${url.trimEnd('/')}/$initialTimestamp"
+        urlValidator.validate(testUrl)
+    }
+
     suspend fun getBalanceForAddressType(addressType: AddressType): Result<ULong> = withContext(bgDispatcher) {
         executeWhenNodeRunning("getBalanceForAddressType") {
             runCatching {

app/src/main/java/to/bitkit/ui/settings/advanced/RgsServerViewModel.kt

@@ -1,9 +1,12 @@
 package to.bitkit.ui.settings.advanced
 
+import androidx.compose.runtime.Stable
 import androidx.lifecycle.ViewModel
 import androidx.lifecycle.viewModelScope
 import dagger.hilt.android.lifecycle.HiltViewModel
 import kotlinx.coroutines.CoroutineDispatcher
+import kotlinx.coroutines.Job
+import kotlinx.coroutines.delay
 import kotlinx.coroutines.flow.MutableStateFlow
 import kotlinx.coroutines.flow.StateFlow
 import kotlinx.coroutines.flow.asStateFlow
@@ -15,7 +18,9 @@ import to.bitkit.data.SettingsStore
 import to.bitkit.di.BgDispatcher
 import to.bitkit.env.Env
 import to.bitkit.repositories.LightningRepo
+import java.net.URI
 import javax.inject.Inject
+import kotlin.time.Duration.Companion.seconds
 
 @HiltViewModel
 class RgsServerViewModel @Inject constructor(
@@ -24,9 +29,20 @@ class RgsServerViewModel @Inject constructor(
     private val lightningRepo: LightningRepo,
 ) : ViewModel() {
 
+    companion object {
+        private val HOSTNAME_PATTERN = Regex(
+            "^([a-z\\d]([a-z\\d-]*[a-z\\d])*\\.)+[a-z]{2,}|(\\d{1,3}\\.){3}\\d{1,3}$",
+            RegexOption.IGNORE_CASE,
+        )
+        private val PATH_PATTERN = Regex("^(/[a-zA-Z\\d_.~%+-]*)*$")
+        private val VALIDATION_DEBOUNCE = 1.seconds
+    }
+
     private val _uiState = MutableStateFlow(RgsServerUiState())
     val uiState: StateFlow<RgsServerUiState> = _uiState.asStateFlow()
 
+    private var validationJob: Job? = null
+
     init {
         observeState()
     }
@@ -47,17 +63,20 @@ class RgsServerViewModel @Inject constructor(
     }
 
     fun setRgsUrl(url: String) {
-        _uiState.update {
-            val newState = it.copy(rgsUrl = url.trim())
-            computeState(newState)
-        }
+        _uiState.update { it.copy(rgsUrl = url.trim()) }
+        debounceValidation()
     }
 
     fun resetToDefault() {
-        val defaultUrl = Env.ldkRgsServerUrl ?: ""
-        _uiState.update {
-            val newState = it.copy(rgsUrl = defaultUrl)
-            computeState(newState)
+        _uiState.update { it.copy(rgsUrl = Env.ldkRgsServerUrl ?: "") }
+        debounceValidation()
+    }
+
+    private fun debounceValidation() {
+        validationJob?.cancel()
+        validationJob = viewModelScope.launch(bgDispatcher) {
+            delay(VALIDATION_DEBOUNCE)
+            _uiState.update { computeState(it) }
         }
     }
 
@@ -72,7 +91,7 @@ class RgsServerViewModel @Inject constructor(
         _uiState.update { it.copy(isLoading = true) }
 
         viewModelScope.launch(bgDispatcher) {
-            lightningRepo.restartWithRgsServer(url)
+            lightningRepo.restartWithRgsServer(normalizeUrl(url))
                 .onSuccess {
                     _uiState.update {
                         val newState = it.copy(
@@ -109,24 +128,25 @@ class RgsServerViewModel @Inject constructor(
         )
     }
 
+    private fun normalizeUrl(url: String): String =
+        if (!url.startsWith("http://") && !url.startsWith("https://")) "https://$url" else url
+
     private fun isValidURL(data: String): Boolean {
-        val pattern = Regex(
-            "^(https?://)?" + // protocol
-                "((([a-z\\d]([a-z\\d-]*[a-z\\d])*)\\.)+[a-z]{2,}|" + // domain name
-                "((\\d{1,3}\\.){3}\\d{1,3}))" + // IP (v4) address
-                "(:\\d+)?(/[-a-z\\d%_.~+]*)*", // port and path
-            RegexOption.IGNORE_CASE
-        )
+        return runCatching {
+            val uri = URI(normalizeUrl(data))
+            val hostname = uri.host ?: return false
 
-        // Allow localhost in development mode
-        if (Env.isDebug && data.contains("localhost")) {
-            return true
-        }
+            if (Env.isDebug && hostname == "localhost") return true
+
+            if (!HOSTNAME_PATTERN.matches(hostname)) return false
 
-        return pattern.matches(data)
+            val path = uri.path.orEmpty()
+            path.isEmpty() || PATH_PATTERN.matches(path)
+        }.getOrDefault(false)
     }
 }
 
+@Stable
 data class RgsServerUiState(
     val connectedRgsUrl: String? = null,
     val rgsUrl: String = "",

app/src/main/java/to/bitkit/utils/UrlValidator.kt

@@ -0,0 +1,5 @@
+package to.bitkit.utils
+
+fun interface UrlValidator {
+    suspend fun validate(url: String): Result<Unit>
+}

app/src/main/java/to/bitkit/viewmodels/WalletViewModel.kt

@@ -328,53 +328,6 @@ class WalletViewModel @Inject constructor(
         }
     }
 
-    private suspend fun checkForOrphanedChannelMonitorRecovery() {
-        if (migrationService.isChannelRecoveryChecked()) return
-
-        Logger.info("Running one-time channel monitor recovery check", context = TAG)
-
-        val allMonitorsRetrieved = runCatching {
-            val allRetrieved = migrationService.fetchRNRemoteLdkData()
-            // don't overwrite channel manager, we only need the monitors for the sweep
-            val channelMigration = buildChannelMigrationIfAvailable()?.let {
-                ChannelDataMigration(channelManager = null, channelMonitors = it.channelMonitors)
-            }
-
-            if (channelMigration == null) {
-                Logger.info("No channel monitors found on RN backup", context = TAG)
-                return@runCatching allRetrieved
-            }
-
-            Logger.info(
-                "Found ${channelMigration.channelMonitors.size} monitors on RN backup, attempting recovery",
-                context = TAG,
-            )
-
-            lightningRepo.stop().onFailure {
-                Logger.error("Failed to stop node for channel recovery", it, context = TAG)
-            }
-            delay(CHANNEL_RECOVERY_RESTART_DELAY_MS)
-            lightningRepo.start(channelMigration = channelMigration, shouldRetry = false)
-                .onSuccess {
-                    migrationService.consumePendingChannelMigration()
-                    walletRepo.syncNodeAndWallet()
-                    walletRepo.syncBalances()
-                    Logger.info("Channel monitor recovery complete", context = TAG)
-                }
-                .onFailure {
-                    Logger.error("Failed to restart node after channel recovery", it, context = TAG)
-                }
-
-            allRetrieved
-        }.getOrDefault(false)
-
-        if (allMonitorsRetrieved) {
-            migrationService.markChannelRecoveryChecked()
-        } else {
-            Logger.warn("Some monitors failed to download, will retry on next startup", context = TAG)
-        }
-    }
-
     fun stop() {
         if (!walletExists) return
 

app/src/test/java/to/bitkit/repositories/LightningRepoTest.kt

@@ -51,6 +51,7 @@ import to.bitkit.services.LightningService
 import to.bitkit.services.LnurlService
 import to.bitkit.services.LspNotificationsService
 import to.bitkit.test.BaseUnitTest
+import to.bitkit.utils.UrlValidator
 import kotlin.test.assertEquals
 import kotlin.test.assertFalse
 import kotlin.test.assertNotNull
@@ -72,6 +73,7 @@ class LightningRepoTest : BaseUnitTest() {
     private val lnurlService = mock<LnurlService>()
     private val connectivityRepo = mock<ConnectivityRepo>()
     private val vssBackupClientLdk = mock<VssBackupClientLdk>()
+    private val urlValidator = UrlValidator { Result.success(Unit) }
 
     @Before
     fun setUp() = runBlocking {
@@ -94,6 +96,7 @@ class LightningRepoTest : BaseUnitTest() {
             preActivityMetadataRepo = preActivityMetadataRepo,
             connectivityRepo = connectivityRepo,
             vssBackupClientLdk = vssBackupClientLdk,
+            urlValidator = urlValidator,
         )
     }
 
@@ -498,6 +501,78 @@ class LightningRepoTest : BaseUnitTest() {
         assertTrue(result.isFailure)
     }
 
+    @Test
+    fun `restartWithRgsServer should setup with new rgs server`() = test {
+        startNodeForTesting()
+        val customRgsUrl = "https://rgs.example.com/snapshot"
+        whenever(lightningService.node).thenReturn(null)
+        whenever(lightningService.stop()).thenReturn(Unit)
+
+        val result = sut.restartWithRgsServer(customRgsUrl)
+
+        assertTrue(result.isSuccess)
+        val inOrder = inOrder(lightningService)
+        inOrder.verify(lightningService).stop()
+        inOrder.verify(lightningService).setup(any(), isNull(), eq(customRgsUrl), anyOrNull(), anyOrNull())
+        inOrder.verify(lightningService).start(anyOrNull(), any())
+        assertEquals(NodeLifecycleState.Running, sut.lightningState.value.nodeLifecycleState)
+    }
+
+    @Test
+    fun `restartWithRgsServer should handle stop failure`() = test {
+        startNodeForTesting()
+        whenever(lightningService.stop()).thenThrow(RuntimeException("Stop failed"))
+
+        val result = sut.restartWithRgsServer("https://rgs.example.com/snapshot")
+
+        assertTrue(result.isFailure)
+    }
+
+    @Test
+    fun `restartWithRgsServer should handle start failure and recover`() = test {
+        startNodeForTesting()
+        whenever(lightningService.node).thenReturn(null)
+        whenever(lightningService.stop()).thenReturn(Unit)
+        whenever(lightningService.setup(any(), isNull(), eq("https://bad.rgs/snapshot"), anyOrNull(), anyOrNull()))
+            .thenThrow(RuntimeException("Failed to start node"))
+
+        val result = sut.restartWithRgsServer("https://bad.rgs/snapshot")
+
+        assertTrue(result.isFailure)
+    }
+
+    @Test
+    fun `restartWithRgsServer should fail when url is unreachable`() = test {
+        val failingValidator = UrlValidator { Result.failure(Exception("DNS resolution failed")) }
+        val sutWithFailingValidator = LightningRepo(
+            bgDispatcher = testDispatcher,
+            lightningService = lightningService,
+            settingsStore = settingsStore,
+            coreService = coreService,
+            lspNotificationsService = lspNotificationsService,
+            firebaseMessaging = firebaseMessaging,
+            keychain = keychain,
+            lnurlService = lnurlService,
+            cacheStore = cacheStore,
+            preActivityMetadataRepo = preActivityMetadataRepo,
+            connectivityRepo = connectivityRepo,
+            vssBackupClientLdk = vssBackupClientLdk,
+            urlValidator = failingValidator,
+        )
+        sutWithFailingValidator.setInitNodeLifecycleState()
+        whenever(lightningService.node).thenReturn(mock())
+        whenever(lightningService.sync()).thenReturn(Unit)
+        val blocktank = mock<BlocktankService>()
+        whenever(coreService.blocktank).thenReturn(blocktank)
+        whenever(blocktank.info(any())).thenReturn(null)
+        sutWithFailingValidator.start()
+
+        val result = sutWithFailingValidator.restartWithRgsServer("https://rapidsync.lightningdevkit/snapshot")
+
+        assertTrue(result.isFailure)
+        assertEquals("DNS resolution failed", result.exceptionOrNull()?.message)
+    }
+
     @Test
     fun `getFeeRateForSpeed should use provided feeRates`() = test {
         val mockFeeRates = mock<FeeRates>()